Control mechanism and shaft lock



July 28, 1959 J. H. GODFREY ETAL CONTROL MECHANISM AND-SHAFT LOCK Filed Aug. 7, 1958 3 Sheets-Sheet l FIG.4

- INVENTORS dAMES H. GODFREY BY KESTUT/S DAM/JONA/T/S M MW A TORNEYS July 28, 1959 J. H. GODFREY ET AL 2,897,302

CONTROL MECHANISM AND SHAFT LOCK Filed Aug. 7, 1958' 5 Sheets-Sheet 2 35 23 4 25 .513 m ,aa I0 27 5? /9 26 z I 25 p :11. I! I I I I I, E 4s /4 55 Z4 /a FIG? INVENTORS dAMES H. GODFREY KES TU r/s DAM/JONA/T/S ATTORNEYS July 28, 1959 J. H. GODFREY ETAL 2,397,302

CONTROL MECHANISM AND SHAFT LOCK Filed Aug. 7, 1958 5 Sheets-Sheet 3 IN V EN TORS JAMES .H GODFREY BY K E6 TU T/5 DAM/JONA/ 775 WWW ATTORNEYS United States Patent 2,897,302 CONTROL MECHANISM AND SHAFT LOCK James H. Godfrey, Berlin, and Kestutis Damijonaitis, Newington, Conn, assignors to The Stanley Works, New Britain, Conn., a corporation of Connecticut Application August 7, 1958, Serial No. 753,790

12 Claims. (Cl. 200-42) This invention relates generally to devices for locking a power-driven shaft against rotation and more particularly to a device of this type having means for interlocking the shaft power control element and the shaft lock.

It is an object of this invention to provide a selfgripping mechanical shaft lock which is interlocked with the shaft drive means to insure removal of shaft power before the lock is engaged.

It is a further object of this invention to provide a single lever switch and shaft lock which is easily operable while being inexpensive to manufacture and reliable to It is a further object of this invention to provide a switch and shaft lock for electrical hand tools which permits easy and safe installation of bits, cutters and other work elements used with the hand tool.

Other objects will be in part obvious and in part pointed out in more detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

in the drawings:

Fig. 1 is a side elevation of a preferred embodiment of our invention;

Fig. 2 is a top view of the embodiment illustrated in Fig. 1 with the top cover removed;

Fig. 3 is a partial cross section of the preferred embodiment taken along the lines 33 of Fig. 2;

Fig. 4 is a front view of the external operating mechanism of the preferred embodiment;

Fig. 5 is a partial plan view of the mechanism in the on position;

Fig. 6 is a front view of the external operating mechanism in the on position;

Fig. 7 is a partial cross section of the mechanism illustrated in Fig. 5;

Fig. 8 is a partial plan view of the mechanism in the lock position;

Fig. 9 is a front view of the external operating mechanism in the lock position and;

Fig. 10 is a partial side elevation of the mechanism shown in Fig. 8.

In the drawings, the invention is shown in a preferred embodiment as applied to the motor body of a powerdriven router. In Fig. 1, the router shown generally as 1 comprises an electric motor frame 2, a front frame 3 and a rear frame 4, frames 2, 3 and 4 being held together by appropriate fasteners. Cover 5 encloses frame 4 and has provision for electrical cable 6 to pass therethrough to energize the motor. Shaft 7 extends beyond frame 3 and carries chuck or collet 8 which is rotatable relative to shaft 7 to exert a gripping force on tool 9, shown as a cutter (in dotted lines). Recessed frame portion 10, integrally formed with frame member 4 in the preferred embodiment, protects control handle 11 from accidental movement while permitting access to handle 11 to enable the operator to turn the motor on and off as well as to lock the shaft in a manner which will be hereinafter described.

Referring now to Figs. 2, 3 and 4 in which the control handle is in the off position, it is seen that motor frame 2 supports stator winding 12 and that frame member 4 acts as a pedestal for ball bearing r13 in which end 14 of shaft 7 rotates. Rotor 15, supported by shaft 14, is shown as being of wound rotor construction with commutator 16 and brushes 17 provided for establishing electrical connection thereto. A second bearing pedestal, carried by frame member 3, supports the other end of shaft 7 in a conventional manner and is not shown. Switch 18, shown in the off position, is supported by frame member 4 in a position such that switch operator 1) is pivotally movable in a plane generally parallel to the axis of shaft 7. Frame member 4 also supports upstanding posts 20 and 21 on opposite sides of and extending beyond shaft 14 so that cross member- 23 can be fastened to their upper ends. As previously noted, frame member 4 is provided with a recessed portion 10 having a side wall which is generally designated as 24. Side wall 24 is provided with .a transversely extending slot 25 having an enlarged portion 26.

The structure thus far described provides the structural environment for a locking bar or lever 27. Referring particularly to Figs. 2, 3, 5 and 8, it is seen that lever 27 has a bifurcated end portion designated generally as 28 whose slot 29 passes around operator 19 of switch 18. The other end of lever 27 extends through slot 25 and terminates in bent-down portion 3i; (see dotted lines, Fig. 3) to which control handle 11 is attached. Lever 27 is provided with an aperture 31 having a first portion 32, generally circular in shape and of diameter greater than end 14 of shaft 7, a rectangular portion 33 and a back portion 34. As most clearly seen in Figs. 3 and 5, end 14 of shaft 7 is provided with opposed flat sides 35, the dimensions of which are approximately equal to the dimensions of aperture 33. To aid in positioning lever 27, leaf spring 36 is provided with a first portion 37 passing through aperture 34 and engaging abutment 38 in frame member 4. Top portion 39 of spring 36 engages cross member 23, and front portion 40 of spring 36 has a portion of reduced width passing through and engaging the front wall of aperture 41 formed in lever 27. The shoulders formed at the point of reduced width engage the periphery of aperture 41 so that spring 36 exerts a downward force between cross member 23 and lever 27 The end of front portion 40 is bent up to prevent withdrawal of spring 36 from aperture 41. Thus, spring 36 acts to urge depending abutment 42 of lever 27 forward into engagement with pin 43 secured in frame member 4 adjacent slot 25 and also urges lever 27 into engagement with the top of abutment 38 and the top of pin 43. Pin 43 is made of hardened steel to provide a long wearing bearing surface. v

The position of the mechanism shown in Figs. 2, 3 and 4 is the off position in which the operating handle 11 is adjacent the off markings on portion 24 of frame member 4, switch 18 is in the off position, and shaft 14 is free to rotate in portion 32 of aperture 31. When lever 27 is moved to the on position shown in Figs, 5, 6 and 7, handle 11 moves to a position adjacent the on designation on portion 24 of frame member 4 as lever 27 pivots about post 21 as a pivot point to move operator 19 of switch 18 to the on position to energize the motor. In this position (see Fig. 5), end 14 of shaft 7 is free to rotate within aperture 31. If operator desires to turn the device off, movement of operating handle 11 to the off position will pivot lever 27 about post 20 to snap operator 19 of switdh 18 to the off position. During normal operation, end 37 of spring 36 is trapped 3 between projecting side walls 45 and 46 of abutment 38 (see Fig. 2) while front end 40 of spring 36 moves with aperture 41 in lever 27. During operation between off and on positions, the arcuate front face of depending abutment 42 rides against the surface of pin 43 and operating handle 11 moves within the recess formed in frame member 4. The recess protects the handle from inadvertent contact which would change the switch setting or attempt to lock the shaft.

When it is desired to lock the shaft against rotation, and assuming the motor to be operating, it is necessary to move lever 27 from the on to the off position as previously described. As clearly seen in Figs. 8, 9 and 10, when in the off position, the front portion of lever 27 is in registry with the enlarged portion 26 of slot 25 formed in frame member 4. An upward force is then exerted on operatinghandle 11 in the direction of the arrow embossed in handle 11 to release abutment 42 from engagement with pin 43 and enable spring 36 to move lever 27 outwardly through the enlarged portion 26 of aperture 25. Assuming that shaft end 14 has stopped rotating and that flat sides 35 are aligned with the side walls of aperture 33, outward movement of lever 27 will continue until projections 33a and 33b, formed at the rear of aperture 33, engage shaft end 14 to limit further outward movement. Shaft 7 is now locked against rotation since its movement is limited by lever 27 whose position is confined by the dimensions of'enlarged portion 26 of aperture 25 and the upright posts 20 and 21. Tool 9 of Fig. 1 can now be changed with a single wrench to loosen chuck 8.

The shaft lock just described is also self-applying in that handle 11 can be pushed up to commence the shaft locking operation even though fiat sides 35 of shaft 7 and the side walls of aperture 33 are not aligned. Under this condition, spring 36 moves abutment 42 of lever 27 in an outward direction beyond pin 43, but further movement is prevented by the failure of the side walls of aperture 33 to line up with the flat sides 35 of shaft end' 14. Manual rotation of shaft 7 to a position in which aperture 33 and flat sides 35 are in alignment, will enable lever 27 to automatically continue its forward movement to complete the shaft locking. This manual rotation would be accomplished in the router embodiment shown in Fig. l by rotation of chuck or collet member 8 to release tool 9.

Chamfered shoulder 26a is provided at the extreme off position of slot 25 and tends to prevent accidental locking of shaft 7 during normal switching from on to off by urging lever 27 in a downward direction. It is thus necessary to move lever 27 toward the on position so as to clear shoulder 26a and enable lever 27 to be pushed up to commence the locking operation.

To release shaft 14 from the locked position shown in Figs. 8 and 10, it is necessary to push operating handle 11 inwardly. During such inward movement, and when abutment 42 has been moved over the top of pin 43, spring 36 will force lever 27 in a downward direction so that abutment 42 again rides against pin 43 and lever 27 is in the unlocked off position from which handle 11 can be moved to the on position to move operator 19 of switch 18 to the on position to energize the motor.

It is therefore seen from the foregoing description that this invention provides an effective and reliable mechanical shaft lock that is interlocked with the shaft power control switch in a manner that prevents locking of the shaft when the power is on or inadvertent energization of the shaft drive means while the shaft is locked. It is further seen that this invention provides a single lever self-gripping shaft lock which is amenable to onehand operation and which is sufficiently inexpensive to construct as to make it usable in a great variety of applications.

As many changes could be made in the above construction and many apparent widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. The control mechanism comprising a power-driven rotatable shaft having an irregularly shaped cross section at one portion in its length, a control element for energizing and de-energizing the drive means for said shaft, a locking bar, means supporting said bar for generally pivotal movement relative to said shaft, said bar having a locking portion engageable with the irregularly shaped portion of said shaft to lock said shaft against rotation, and means operatively connecting said bar and said control element whereby pivotal movement of said bar actuates said control element to energize and deenergize said motor, said bar being movable into locking engagement with said shaft after said control element has de-energized the shaft drive means.

2. The control mechanism comprising a power-driven rotatable shaft having an irregularly shaft cross section at one portion of its length, a switch for energizing and de-energizing the drive means for said shaft, said switch having a pivotally movable operator, a locking bar, and means supporting said bar for generally pivotal movement relative to said shaft, said bar having a locking portion thereon engageable with said irregularly shaped portion of said shaft to lock said shaft against rotation and having a slotted end portion in engagement with said operator for said switch whereby pivotal movement of said bar actuates said switch to energize and de-energize the drive means for said shaft, said bar being movable into locking engagement with said shaft after said switch has de-energized the shaft drive means.

3. The control mechanism comprising a power-driven rotatable shaft, opposing flat sides on said shaft at one portion in its length, a control element for energizing and de-energizing the drive means for said shaft, a locking bar, means supporting said bar for generally pivotal movement relative to said shaft, said bar having a slot formed therein dimensioned to be engageable in a complementary manner with the opposed flat sides of said shaft thereby to lock said shaft against rotation, and means carried by said bar and engageable with said control element whereby movement of said bar actuates said control element to energize and de-energize the drive means for said shaft, said bar being movable into locking engagement with said shaft after said switch has de-energized the shaft drive means.

4. The control mechanism comprising a power-driven rotatable shaft having irregularly shaped cross section at one portion in its length, a control element for energizing and de-energizing the drive means for said shaft, a locking bar, means supporting said bar for pivotal and sliding movement relative to said shaft, means carried by said bar and engageable with said control element whereby pivotal movement of said bar actuates said control element to energize and de-energize said motor, a locking portion on said bar engageable with the irregularly shaped portion of said shaft, said engagement being effected by sliding movement of said bar relative to said shaft thereby to lock said shaft against rotation, and means preventing sliding movement of said bar into locking engagement with said shaft when said control element is in the shaft drive means energizing position.

5. The control mechanism as set forth in claim 4 wherein said means preventing sliding movement of said 6. The control mechanism comprising a power-driven rotatable shaft having an irregularly shaped cross section at one portion in its length, a switch for energizing and de-energizing the drive means for said shaft, a locking bar, means supporting said bar for pivotal and sliding movement relative to said shaft, said bar having means for engaging the operator of said switch whereby pivotal movement of said bar actuates said switch to energize and de-energize said motor, a locking portion on said bar slidably engageable with said irregularly shaped shaft portion thereby to lock said shaft against rotation, and stop means for preventing sliding movement of said bar, said stop means being disengageable when said switch has de-energized the shaft drive means.

7. The control mechanism as set forth in claim 6 wherein the irregularly shaped cross section of said shaft comprises opposed fiat sides on said shaft, and said locking portion on said bar comprises a slot formed in said bar, said slot having a configuration mating with said opposed flat sides.

8. The control mechanism comprising a power-driven rotatable shaft having an irregularly shaped cross section at one portion in its length, a control element for energizing and de-energizing the drive means for said shaft, a locking bar, an aperture formed in said locking bar and having a first portion dimensioned larger than the cross section of said shaft and a second portion dimensioned to engage the irregular portion of said shaft in a complementary manner, means supporting said bar for generally pivotal movement about said shaft and for sliding movement in a plane transverse to said shaft, means carried by said bar and engageable with said control element whereby pivotal movement of said bar actuates said control element to energize and de-energize the drive means for said shaft, and stop means for preventing sliding movement of said bar, said stop means being disengageable when said control element has de-energized the shaft drive means.

9. The control mechanism as set forth in claim 8 wherein said stop comprises a depending projection on said bar, an abutment carried by said supporting means and engaged by said depending projection during pivotal movement of said bar, said projection being releasable from said abutment by upward movement of said bar.

10. The control mechanism as set forth in claim 8 wherein said stop comprises a depending projection on said bar, an abutment carried by said supporting means and engaged by said depending projection during pivotal movement of said bar, and an upstanding frame member having a transversely extending slot formed therein in which said bar is pivotally movable, said slot having an enlarged section in which said bar can be moved upward to release said projection from said abutment.

11. The control mechanism for an electrically driven tool comprising a power driven rotatable shaft having opposed flat sides at one point in its length, a switch having a pivotally supported operator therefor, said switch being operable to energize and de-energize the drive means for said shaft, a locking bar, an aperture formed in said bar having a circular portion of diameter greater than said shaft and a slot portion contiguous with said circular portion and having dimensions complemen-' tary to said shaft flat sides, means supporting said bar for generally pivotal movement about said shaft and for sliding movement in a plane transverse to said shaft, said bar having a bifurcated end portion in engagement with said switch operator whereby pivotal movement of said bar actuates said control element, a stop mechanism for limiting sliding movement of said bar comprising a depending projection on said bar, and an abutment on said supporting means engaged by said depending projection during pivotal movement of said bar, said projection being releasable from said abutment by upward deflection of said bar when said bar is in the pivotal position representing the de-energized position of said control means thereby to permit sliding movement of said bar to bring said slot portion of said aperture into locking engagement with said shaft.

12. The control mechanism comprising a power-driven rotatable shaft having opposed flat sides at one portion in its length, a switch for energizing and deenergizing the drive means for said shaft, a locking bar, an aperture formed in said locking bar and having a first portion dimensioned larger than the cross section of said shaft- References Cited in the file of this patent UNITED STATES PATENTS Carter May 12, 1931 Kurtovi'ch Sept. 24, 1957 

